The drivers of forest carbon sink density changes in China under forest area heterogeneity: A production-theoretical decomposition analysis

Global temperatures continue to rise, and mitigating climate change has become a common global challenge. As a nature-based solution, forest carbon sink has received high recognition from the international community for its role in mitigating climate change. However, traditional production theory decomposition analysis (PDA) fails to consider regional heterogeneity when exploring the drivers of forest carbon sink. To better formulate strategies for enhancing forest carbon sink based on the specific conditions of each region, this study proposes a PDA method integrated with the meta-frontier model. The new model applied to the forest carbon sink density (FCSD) of 30 provinces in China in 2018. It analyses the driving mechanisms of forest land area inputs, forest pests and diseases infestations, and heterogeneity on the FCSD in state-owned forest areas, southern collective forest areas, and mixed forest areas. The model decomposes them into three primary factors and three substitute factors. The study results indicate the following: (1) After considering heterogeneity, the FCSD shifted from state-owned forest areas toward southern collective forest areas, further indicating that state-owned forest areas still have significant potential for improving forest carbon sink; (2) Further analysis of the two-stage factor substitution effects unrelated to heterogeneity reveals that the varying degrees of substitution among forest land, labor, and capital have different impacts on FCSD; (3) The primary driving factors differ among different forest areas. Results from multiple factors indicate that mixed forest areas perform poorly, further widening forest carbon sink distribution gaps nationwide.